An ancient, in-bred, pure-blood wizarding family living in slovenly
conditions in a shack in Little Hangleton. Family members include the
father Marvolo, and a son Morfin and a daughter named Merope. The Gaunts
were the last remaining descendents of Hogwarts co-founder Salazar
Slytherin. Once a wealthy family; by the 1940s, they were best known
for their instability and violent behavior.

Most of what we know about them comes from Dumbledore's interview
of Ministry of Magic investigator Bob Ogden (HBP10). Ogden went to
the Gaunt house to serve a summons on Morfin Gaunt.

They lived in a dilapidated shack on a heavily wooded hillside above
the town of Little Hangleton. When Harry saw Ogden's memory in the
Pensieve, there was a snake nailed to the door. Inside there are three
very small rooms. The main room is filthy and squalid.

Name meaning?To be gaunt is to be "very thin especially from disease or hunger or cold." (Wordnet)

Marvolo Gaunt
Marvolo is shorter than his son Morfin, with odd proportions. He has "bright brown
eyes, short scrubby hair, and wrinkled face." Harry think he looks like
a powerful, aged monkey (Salazar Slytherin is also
described as "monkey-like" in CS17).
Marvolo wore a gold ring with
the Peverell coat of arms carved into a black stone
(HBP10).

Marvolo attacked Ministry personnel who had come to arrest his son,
so he too was arrested. He was convicted by the Wizengamot and sentenced
to Azkaban for 6 months
(HBP10).
He died before his son's sentence was complete.

Merope Gaunt
Merope Gaunt was the daughter of Marvolo Gaunt and mother of Tom Riddle. Eighteen-year-old Merope's hair is lank and dull and she has a "plain,
pale, rather heavy face." Her eyes also gaze in opposite directions. Merope's
father is extremely abusive to her and derisively calls her a
"Squib" (and
other dreadful things). It is no wonder that Harry observes that she looks "defeated." In
addition to ragged clothing, Merope wears a heavy gold locket that her father
claims belonged to Salazar Slytherin (HBP10).

Merope was intensely attracted to the wealthy Muggle Tom Riddle, but
there were a couple problems. She knew her father would be violently
opposed, and Tom saw her as an object of derision and disgust. However,
after her brother and father were sent to Azkaban, Merope tricked Riddle
into marrying her with a love potion. It is unknown why, but after
she became pregnant she allowed the potion to wear off and Riddle abandoned
her. Merope went to London, but was so destitute she sold her priceless
gold locket to Caractacus Burke of Borgin & Burke's for a meager
10 galleons. Later she gave birth at a Muggle orphanage and died after
naming her child Tom Marvolo Riddle.

Merope=Eyes or face turned (Greek). "The Pleiades are called
seven in number, but only six can be seen. This reason has been advanced,
that of the seven, six mated with immortals; the seventh was said
to have been the wife of [mortal] Sisyphus ... On account of her
other sisters she was placed among the constellations, but because
she married a mortal, her star is dim." - Hyginus,
Astronomica. An unrelated Merope was a Queen of Corinth and Oedipus'
foster mother.

Morfin Gaunt
Morfin Gaunt was the son of Marvolo Gaunt. He is first seen dressed in rags, his thick hair so matted with dirt the color
was indistinguishable. He was missing several teeth, and his eyes, like those of his father and sister, looked in opposite directions. Morfin is a Parselmouth and a sociopath.

Morfin is summoned to a hearing by the Ministry for hexing a Muggle
(Tom Riddle). When he resists he is arrested, convicted, and sentenced
to 3 years at Azkaban (HBP10).

Years later, his nephew Tom Riddle paid him a visit. It was then that
Tom learned that his father was a Muggle. Tom Stupefied Morfin, then
went to the Riddle house and murdered his father and grandparents. Before
leaving Little Hangleton, Tom stole the gold ring that was a Gaunt family heirloom. When questioned by the Ministry, Morfin confessed
to the murders, so Tom must have also implanted false memories. Morfin
died at Azkaban during his second incarceration (HBP17).

'Morfin' is probably a homonym for the powerful drug Morphine,
a highly addictive pain reliever. The word morphine, in turn, is
rooted in the name 'Morpheus,' the Greek god of sleep and dreams.